Calculations and reporting
The assessors will not do any direct calculation of indicators.They will fill in a Kobo form for each species with information on Ne
and/or Nc, populations maintained, numerous other characteristics,
references, maps, etc. For most species the Nc, census size, will be the
main data collected, rather than Ne. If Ne is estimated in the report or
publication it should be reported, of course. However, assessors
should not calculate Ne from Nc manually at this point- it will be
calculated as follows after all data collection is complete.
After all species and populations are reported for a country, for all
cases in which Nc was recorded, the colleagues involved in data analysis
(see project roles spreadsheet) will then apply at least two Ne/Nc
ratios to all populations in order to obtain Ne estimates from Nc- the
0.1 as a conservative default for all species, and a taxon specific one
(either from that species or from a general taxa such as 0.3 for
plants). We will do this in multiple ways to generate confidence bounds
for reporting in the National Reports (a low and a high estimate of Ne).
This will be done also in the case of multiple estimates of Nc for a
population of a given species. This would result in, for example,
potentially four values: low and high Nc estimates and low and high
Ne/Nc ratio assumptions.
Then all Ne values (directly extracted, and calculated from Nc) will be
compared to Ne 500. Every species will receive a ratio of populations
above Ne 500. This will be reported as a proportion, but the original
ratio (including total number of populations) can also be retained.
The country indicator value is the mean across species (a median could
be used for skewed distributions). If taxonomic groups are not
represented evenly (as is likely), the indicator value is the mean of
each taxonomic group’s means, which would downweight taxonomic groups
that are overly represented, e.g. mammals or birds. Optionally, each
species can be weighted by the proportion of its geographic range in the
country, from 0 to 1, to reflect national responsibility, with full
weight for endemic species (REF).
The indicator is easily disaggregated to different taxonomic groups by
only including species in that taxonomic category. The same can be done
for different habitats, species commonness, etc.